A New Push to Solve Wireless Charging

Why It Matters

Battery life is the bane of most mobile devices.

For all the new features, functions, and blazing speeds of the latest mobile devices, most still share a common downside: limited battery life that eventually forces you to be tethered to a power cord and outlet.

There should be a solution to this by now. The electronics industry has been working on wireless charging for years, but without agreement on a common way to do it (see “Wireless Charging—Has Its Time Finally Arrived?”). A few products, such as Nokia’s Lumia 920, can be charged wirelessly, but those use a basic magnetic induction technology that requires a special pad on which to place the device.

Now the industry is starting to coalesce around a variant of wireless charging that has a much greater range, meaning devices won’t have to be placed directly on special pads. Instead, several devices at once could get a charge merely from being placed on a table with a charger underneath or nearby. That should make it far easier to charge your device more frequently and keep the battery from ever getting too low.

The company that holds the foundational patents on this technique (see “Charge Your Phone and Your Car from Afar”), Witricity of Watertown, Massachusetts, joined forces with an industry alliance this month, ending a logjam. That industry group, called the Alliance for Wireless Power, has just launched a consumer brand of longer-range wireless charging devices, called Rezence. “All the major players have started either thinking about or adopting this technology,” says Kaynam Hedayat, vice president of product manufacturing and marketing at Witricity.

The technology could be seen this week in an obscure booth at the vast Mobile World Congress in Barcelona, Spain. Managers from Samsung and chipmaker Qualcomm showed off how it works. They put an iPhone, Galaxy 3, and Qualcomm Toq headset on a table, and the devices blinked to life. A charging pad had been screwed underneath the table surface and its range was tuned to a specific distance, in this case around 4.5 centimeters, the thickness of the tabletop.

In wireless charging systems, a current is passed through a coil to generate an electromagnetic field, which creates another electric current in a coil in a nearby device. But in existing devices, such as the Lumia phone, the adjacent coil has to be positioned very closely—hence the special pad. In the new version, called highly resonant technology, the sending and receiving coils are tuned to resonate at a specific frequency, allowing charging at larger distances.

As a practical matter, this means charging pads can be bolted beneath existing surfaces at restaurants, airport waiting areas, and many other settings. And users can casually place devices within the area and get a charge.

In restaurants around Barcelona during Mobile World Congress this week, it was common to see conference-goers handing $600 mobile devices and power cables to bartenders and waiters, asking them to plug in their dead electronics behind the bar for a tip of a couple of euros. Next year, though, it’s likely that many conference-goers will just put their phones on the bar in front of them—rather than behind it.